Designed to open at 160 degrees, regardless of engine rpm, and it's high-flow design and brass and copper construction eliminate the damaging effects of cycling when you're stuck in stop-and-go traffic. It includes the rubber gasket and has a pressure relief valve. Features: Opens sooner than stock at 160 degrees High flow design for performance applications Includes rubber o-ring seal/gasket Incorporates pressure relief valve Fits 2004-2008 GM LS2/LS3/LS6/LS7 and 1997-2003 LS Engines when using Mr. Gasket Water Necks 2670, 2671, and 2672.